A multi-cylinder internal combustion engine typically includes a plurality of cylinder heads which are attached to and cover corresponding combustion cylinders. Each cylinder head may include an inlet air channel and an exhaust channel which are disposed in fluid communication with a corresponding combustion cylinder. The inlet air channel and the exhaust channel may include an inlet valve seat and an exhaust valve seat which are opened and closed using an inlet valve and an exhaust valve, respectively. An internal combustion engine with a plurality of larger combustion cylinders may include multiple inlet valve seats and exhaust valve seats to ensure that the combustion air and exhaust gasses are transported into and away from the combustion cylinder.
With a cylinder head having an air inlet channel with multiple inlet valve seats as described above, it is known to place the inlet valve seats in a series arrangement within the inlet air channel such that combustion air passes over a first inlet valve seat and terminates at a second inlet valve seat. A problem with this type of configuration is that most of the combustion air passes over the first inlet valve seat and flows through the second inlet valve seat disposed at the end of the inlet air channel. The combustion air is therefore not evenly introduced into the combustion cylinder through the inlet valve seats, and may not ensure that an adequate supply of combustion air is introduced into the combustion cylinder. Additionally, the push rods associated with each cylinder head typically pass through an opening defined by the cylinder head which is disposed in the inlet opening of the inlet air channel. The push rods and associated carrying structure of the cylinder head therefore impede the flow of combustion air through the inlet air channel through the combustion cylinder. Such a cylinder head is known as a "cross-flow" cylinder head.
It is also known to provide a cylinder head with multiple inlet air channels which each terminate at a respective inlet valve seat. Such a cylinder head configuration avoids the problems associated with a "cross-flow" configuration, but also adds additional structure to the cylinder head which increases the size and manufacturing costs and complexity of the cylinder head.
The present invention is directed to overcoming one or more of the problems as set forth above.